Smoking articles

ABSTRACT

This invention relates to a smoking article or smoking-article component having wrapped around it a band or strip of material shrinkable by the heat of hot smoke from the approaching coal when the article is smoked. Such a band may be wrapped around the tobacco rod of the article near the end to be placed in the mouth, around a filter or mouthpiece or around a body of smokeimpermeable material disposed between the tobacco rod and a filter or mouthpiece. Such a band may also be disposed inside a wrapping section of perforated or air-pervious material so as to close the said material against the passage of air until shrinkage occurs.

United States Patent 1191 Horsewell et al.

1 51 Apr. 2, 1974 SMOKING ARTICLES [73] Assignce: Brown & Williamson Tobacco Corporation, Louisville, Ky.

I22] Filed: Oct. 3, 1972 [211 App]. No.: 294,691

[30] Foreign Application Priority Data Oct. 1 1, 1971 Great Britain 47237/71 [52] US. Cl 131/l0.3, 131/4 A, 131/8 A, 131/10 A [51] Int. Cl A24d 01/10 [58] Field of Search 131/4 A, 10.3, 8 A, 170 A, 131/171A,1l

2,815,028 12/1957 Bernhard 131/8 A 3,602,232 8 1971 Grauvogel 131 10.5 3,621,851 11 1971 Heskettetal 131/105 FOREIGN PATENTS OR APPLICATIONS 72,589 9/1931 Sweden 131 4 A 659,839 6/1965 Bclgium..... 131 4 A 1,553,960 12/1968 France 131 4 A 149,216 11 1952 Australia 131 4 A Primary Examiner-Robert W. Michell Assistant Examiner-John F. Pitrelli Attorney, Agent, or Firm-Finnegan, Henderson, Farabow & Garrett [57] ABSTRACT This invention relates to a smoking article or smokingarticle component having wrapped around it a band or strip of material shrinkable by the heat of hot smoke from the approaching coal when the article is smoked. Such a band may be wrapped around the tobacco rod of the article near the end to be placed in the mouth, around a filter or mouthpiece or around a body of smoke-impermeable material disposed between the tobacco rod and a filter or mouthpiece. Such a band may also be disposed inside a wrapping section of perforated or air-pervious material so as to close the said material against the passage of air until shrinkage occurs.

2 Claims, 18 Drawing Figures PATENTEDAPR 2mm 3800 805 sum 1 or 5 PATENIEUAPR 2 074 SHEEI 2 BF 5 PATENTEDAPR 2|974 SHEET 3.0F 5

PATENTEU APR 2 I974 SHLET U HP 5 F IG.I4.

?ATENTEDAPR 21974 $800,805

sum 5 OF 5 7 FIG. l7

SMOKING ARTICLES This invention is concerned with improvements relating to smoking articles, particularly filter and other cigarettes, and to filter or mouthpiece components thereof.

An object of the invention is to provide means for effectively reducing the delivery of particulate matter of tobacco smoke and/or modifying the supply of air, especially in the last few puffs of a cigarette.

According to the invention, a band or strip of a heatshrink material is wrapped around a filter and/or mouthpiece component and/or a portion of a tobacco rod of a smoking article. Thus, a filter component and- /or the end of the tobacco rod of a cigarette may be so wrapped with a strip of heat-shrink film material that, when the cigarette is smoked and the burning coal approaches, hot smoke from it will cause the said material to shrink, thereby causing constriction and increasing the pressure drop to such an extent that the passage of smoke will be substantially hindered or even prevented. Since the delivery of total particulate matter, as well as nicotine, on a per-puff basis normally increases rapidly for the last few puffs, the use of the heat-shrink material will reduce the delivery of total particulate matter.

The band or strip of heat-shrink material may additionally or alternatively be arranged to control a supply of ventilating air through a wrapping section of perforated or air-porous material.

The accompanying diagrammatic drawings illustrate several forms of embodiment of the invention as applied to cigarettes. In the pairs of figures, FIGS. 1 and 2, FIGS. 3 and 4 and so forth, through FIGS. 17 and 18, the first and second figures of each pair are longitudinal sections through part, near the mouth end, of a cigarette before and after smoking, respectively.

In the embodiment of FIGS. 1 and 2, a cigarette comprising tobacco in a paper wrapping 2 is encircled at or near the mouth end by a narrow band or strip 3 of heat-shrink film material. This band is secured to the wrapping 2 by adhesive, for instance at narrow end zones 4 and 5. On smoking the cigarette, when the burning coal approaches the band 3, the latter will shrink as it is heated by hot smoke from the coal, so that the circumference of the end of the cigarette will be reduced (FIG. 2) and the pressure drop increased to such an extent that the cigarette becomes difficult to draw or even incapable of being smoked beyond this stage.

The cigarette of FIGS. 3 and 4 has a filter section or plug 6 enclosed in a wrap 7 which is encircled in turn by a band 8 of heat-shrink material. The assembly 6-8 is connected to the cigarette wrapping 2 in known manner by paper tipping 9. The band 8 is secured to the wrap 7 by adhesive at narrow end zones at 10 and 11 and the tipping 9 is similarly secured to the band 8 and to the wrapping 2 at end zones at 11 and 12 respectively. The filter section 6, which may be of slightly larger diameter than the tobacco rod 1, is composed of fibrous material or open-cell foam material, for example plasticised or unplasticised cellulose acetate, viscose, paper or flocculated filter material, or polyurethane or polyethylene foam material. In this case, when the band 8 shrinks on being heated by the hot smoke from the approaching coal, it will compress the material of the filter section 6 adjacent to the tobacco (FIG.

4). The pressure drop will thereby be increased to such an extent that the passage of smoke is greatly hindered. With a dual or multiple filter, the arrangement of FIGS. 3 and 4 may beapplied to the filter section adjacent to the tobacco rod.

In the embodiment of FIGS. 5 and 6, a body 13 of material impermeable to air and smoke and of slightly smaller diameter than the filter section 6 is interposed between the latter and the tobacco l. A band 14 of heat-shrink material located under the tipping 9 is connected at end zones 15, 16 to the wrapping 2 and'filter wrap 7 respectively, an annular gap 13a being left between the said band and the body 13. When heated by the hot smoke, the band 14 will shrink onto the impermeable body 13, thereby closing the gap 13a FIG. 6). In effect, the filter is completely blocked and further puffs can no longer be taken. The body 14 may be made of wax, closed-cell plastic foam or other impermeable material. As shown, it is spherical, but it may be of cylindrical or disc form.

In the cigarette of FIGS. 7 and 8, perforations 17, for example two or three rings of perforations, are provided in the tipping 9 where it overlies a band 18 of heat-shrink material secured at 15 to the wrapping 2. An impermeable body 13, in this case of cylindrical form, is again interposed between the tobacco 1 and filter section 6. When the band 18 is heated and shrinks onto the impermeable body 13, closing the gap 13a between the band 18 and body 13, the holes 17 will be uncovered, thus replacing the smoke by air (FIG. 8).

With a similar arrangement, however, either the effect of reducing or cutting off the smoke or the effect of replacing the smoke by, or diluting it with, air can be achieved.

Perforations may be similarly provided in other embodiments of the invention. For example, with the embodiment of FIGS. 3 and 4, rings of perforations may be provided at 17a (FIG. 4) in the tipping 9 where they will be closed by the band 8 until the latter shrinks. As shown in FIGS. 9 and 10, perforations at 17b in the tipping 9 may be similarly uncovered (FIG. 10) by the shrinkage of a band 20 of heat-shrink material encircling the end of the wrapped tobacco rod 1. If smoke replacement or dilution is not required, however, the arrangement of FIGS. 9 and 10 may be used without the perforations at 1712.

FIGS. 11 and 12 illustrate a further arrangement in which smoke-dilution or ventilation is provided. Interposed between the filter section 6, which may be of conventional filter material, and the tobacco rod 1 there is a further filter section 21, preferably of material of softer consistency. This is encircled by a band 22 of heat-shrink material which over-wraps 2-3 mm onto the tobacco rod. The tipping 9 has rings of perforations at which are closed. by the band 22 until it shrinks (FIG. 12), compressing the filter section 21. Thus, at the same time as air is admitted through the perforations at 170, the resistance to smoke flow through the filter section 21 is increased. If desired, however, provision may be made for the smoke to by-pass the compressed filter section, although it is still diluted. An arrangement similar to that illustrated may be used with a triple filter, in which case the heat-shrink band may be arranged to compress the tobacco-end section or middle section. With such arrangements, the whole filter assembly may be additionally wrapped in porous paper.

Instead of providing perforations in the tipping wrap 9, a wrap section of porous paper may be employed.

The invention can also be applied to filter devices of the kind in which a filtering diaphragm, particularly a tubular such diaphragm, extends substantially axially of the filter, the heat-shrink material being arranged to produce eventual closure or constriction of the smoke path through the filter. In the filter device of this kind shown in FIGS. 13 and 14, a cylindrical sleeve 23 of heat-shrink material is fitted loosely and with a gap 23a around the central tube 24, of porous filter paper, of a tubular filter. Alternatively, the sleeve 23 may hang over the tube 24 and may be held to the latter by a line of adhesive where it rests thereon. The tube 24 is mounted in a non-permeable container or mouthpiece 25. The tube 24 is closed by a cap 26 at the end towards the tobacco rod 1, but is open at the other end, while the container 25 is open at the former end and closed at the latter end. Smoke normally passes through the filter in the manner indicated by arrows in FIG. 13. When heated by hot smoke from the approaching coal, however, the sleeve 23 will shrink onto the tube 24 (FIG. 14) hindering or completely blocking the passage of smoke. The paper tube 24 may be replaced by a tube of non-permeable material containing perforations.

Alternatively, with a diaphragm type of filter device, the heat-shrink material may be arranged to effect closure or constriction of the entry to the space on the upstream side of the diaphragm or of the exit from the said device or of some intermediate part thereof.

The arrangement shown in FIGS. and 16 is similar to that of FIGS. 5 and 6, except that the body 13' of impermeable material, in this case a cylindrical body, is interposed between two filter sections 6 and 6, the diameter of the said body being slightly less than that of the said sections. The band 14 of heat-shrink material is secured to the sections 6 and 6' by adhesive at zones 27 and 28 respectively. The tipping 9 is secured at zones 27 and 29. When the band 14' shrinks (FIG. 16) it will close the gap 130 and block the smoke path. A similar arrangement may be provided between a filter and a mouthpiece.

The arrangement of FIGS. 17 and 18 is similar to that of FIGS. 3 and 4, with the exception that the band 8 of heat-shrink material is extended over the end of the tobacco rod 1 to the wrapping 2 of which it is secured by adhesive at a narrow zone 30. When the band 8' shrinks, the end of the tobacco rod 1 will be compressed (FIG. 18) as well as the adjacent part of the filter section 6.

Suitable heat-shrink film materials which may be employed are polyvinylidene chloride, polypropylene, polyester and polystyrene materials, but a polyvinyl chloride or polyethylene material is preferably used. The extent of shrinkage will depend upon the specification and conditions of use of the film material, such as shrink temperature, energy, degree and thickness. It may also be affected in some cases by the nature of the filter material used. The butt length left when blocking or partial blocking of the cigarette or filter occurs will depend on the film material, particularly on its shrinkage temperature.

Preferably, a film material is used which will give unidirectional shrinkage, this being applied in the circumferential direction. However, a material with shrinkage in the longitudinal as well as the transverse direction may be employed.

Coloured heat-shrink film material may be employed for the sake of attractive appearance, especially in the case of ventilated filter cigarettes.

For producing the tubular bands of heat-shrink film material, it is necessary to seal overlapping edges of the material together to produce a longitudinal joint. This sealing may have to be performed during the production of a filter rod. The sealing can be simply performed by applying a solvent for the material to the said edges, folding the edges together and subjecting them to gentle heat. The solvent may be applied by conventional techniques such as a wick or a pasting wheel. Ketonetype solvents, such as methyl ethyl ketone, methyl isobutyl ketone, acetone and cyclohexanone, the last together with tetrahydrofurane, or an alcohol, for instance tetrahydrofurfuryl alcohol, may be used. A thickening agent, such as a cellulose derivative, may be added to the solvent. Adhesives known for joining polyvinyl-chloride film may also be used.

Examples illustrating results obtainable by the use of the invention will now be given.

EXAMPLE 1 A filter section 15 mm long composed of cellulose acetate and wrapped in the manner shown in FIG. 3 (without perforations at 17a) in a band of heat-shrink film material of the polyvinyl chloride type supplied by the Goodyear Tyre and Rubber Co. under the designation VITAFILM was attached to a cigarette and machine smoked under standard conditions of l puff per minute of 35 ml volume and 2 seconds duration. The pressure drop of the filter increased from 6 cm water gauge before shrinkage of the band to 20 cm after shrinkage.

EXAMPLE 2 The pressure drop of a 15 mm long filter section composed of paper and similarly wrapped increased from 6 cm to 15 cm water gauge.

EXAMPLE 3 A triple filter composed of a 7 mm long section of closed-cell polyethylene foam between a 6 mm long section of cellulose acetate at the tobacco end and a 7 mm long section of cellulose acetate was wrapped, in the manner shown in FIG. 15, in the heat-shrink material referred to in Example 1, the foam section being of slightly smaller diameter than the others. Initially the filter had a pressure drop of 4 cm water gauge, but it was found to become completely blocked on shrinkage of the wrapper.

EXAMPLE 4 In an arrangement generally similar to that of FIG. 1, a cigarette was provided at a distance of 8 mm from the mouth-end with an encircling band, 5 mm wide, of the aforesaid heat-shrink material. On smoking the cigarette under standard conditions, the pressure drop of the rod increased from 8 cm to 22 cm water gauge after the cigarette had been puffed 6 or 7 times. A comparable normal-length cigarette takes about 10 puffs to smoke.

EXAMPLE 5 A filter cigarette was produced with a l5 mm long filter section composed of cellulose acetate of 1.6/48,000 denier which was wrapped, in the manner shown in FIG. 17, in a band of heat-shrink film material of the polyvinyl chloride type supplied by W.R. Grace Ltd. under the designation CRYOVAC VPMX. The material extended over the tobacco rod to a distance of 5 mm. The pressure drop of this cigarette increased, on smoking, from 13 cm before shrinkage of the said material to 59.5 cm water gauge after shrinkage thereof. The cigarette would have been discarded by a smoker after about 9 puffs and at a pressure drop exceeding 25 cm. The decrease in the delivery of total particulate matter (TPM) was about 34 percent.

EXAMPLE 6 With a cigarette similar to that of Example 5 but having a 15 mm filter section of cellulose acetate of 15/64,000 denier, the pressure drop increased from 8.2 to 45.5 cm water gauge.

EXAMPLE 7 A 15 mm filter section composed of viscose fibres and wrapped as in FIG. 3 (without perforations at 17a) in a band of the heat shrink material referred to in Example was attached to a cigarette and smoked under the standard conditions. The pressure drop of the filter increased from 3 cm to 15 cm water gauge.

EXAMPLE 8 A dual filter composed of a 10 mm section of cellulose acetate and a 5 mm section of closed-cell polyethylene foam material was attached to a cigarette, with the section of foam material adjacent to the tobacco, generally as in FIG. 7 (without perforations at 17). A band of the heat-shrink material referred to in Example 5 was wrapped around the 5 mm section and overlapped the tobacco rod by 5 mm. the circumference of the closed-cell foamsection was 1 mm smaller tl that of the cigarette. The pressure drop of the filter was initially 12 cm water gauge. On smoking the cigarette under the standard conditions, the filter was found to become completely blocked after about 7 puffs. The TPM was reduced to about 50 percent in relation to a comparable, normal filter cigarette smoked to an 8 mm butt.

.E PEF 9 A 15 mm filter section of cellulose acetate was wrapped in a band of heat-shrink film material of the polyvinyl chloride type supplied under the designation Spicer Cowan BS2" and was attached to a cigarette, generally as shown in FIGS. 3 and 4, with a tipping paper provided (as at 17a in FIG. 4) with two rings of perforations at 2.5 and 4.5 mm from the tobacco end of the filter. The perforations were square, each having an area of 0.084 mm and there were 33 perforations in each ring. On smoking the cigarette through this filter under the standard conditions, the TPM delivery was found to be reduced from 25 mg to 14 mg as compared with a similar filter cigarette, but without the heat-shrink band.

EXAMPLE 10 In an arrangement generally as shown in FIG. 11, but with porous tipping paper, instead of the tipping 9 with perforations at 17, a dual filter composed of a 5 mm section and a 10 mm section of cellulose acetate was attached to a cigarette with the 5 mm section adjacent to the tobacco rod. The 5 mm section was wrapped with a band of the heat-shrink material referred to in Example 5, which also extended 5 mm over the tobacco rod. A tipping paper having a porosity of 13,600 cm /minute/1O cm /10 cm water gauge was used for assembly of the filter in known manner. On smoking the cigarette through this filter under the standard conditions, the TPM was reduced from 38 mg to 23.4 mg as compared with a cigarette having a similar filter used in the normal manner.

EXAMPLE 1 1 A cigarette was provided with a filter similar to that of Example 10 except that the 5 mm section wrapped in the heat-shrink band was a body of smaller diameter than the other section and made of impermeable material as described with reference to FIG. 7. This body was composed of closed-cell polyethylene foam material and the tipping paper was perforated over the part encircling the said body. On smoking the cigarette, the TPM was found to be reduced from 38 mg to 25 mg as compared with a cigarette having a similar filter used in the normal manner.

EXAMPLE 1 2 With a filter-cigarette arrangement such as is shown in FIG. 9 (withoutperforations at 17b), a 5 mm length of the tobacco rod 1 was wrapped in a band of polyvinyl chloride, heat-shrink material. With this provision, the pressure drop was found to increase from 1 1 cm to 33 cm water gauge on smoking the cigarette under standard conditions.

EXAMPLE 13 In a filter device such as is shown in FIG. 13, the sleeve of heat-shrink material had a diameter l-2 mm larger than that of the central paper tube. On smoking a cigarette through this device, whose pressure drop was initially 13 cm water gauge, the filter became completely blocked on shrinkage of the material. I

We claim:

1. A smoking article comprising: an elongated smoking article component; a length of air permeable material wrapped about a section of said component; a band of air impermeable, heat shrinkable material disposed at least in part between said component section and said air permeable material in position so as normally to close the air permeable material against the passage of air while at the same time leaving a longitudinal passage for smoke through said component; and a body disposed in and at least partially blocking said longitudinal passage whereby when said heat shrinkable material is heated it will shrink onto said body thereby at least partially restricting said passage and uncovering the air permeable material to admit outside air into the article, wherein said body is formed of a material impermeable to air and smoke.

2. A smoking article comprising: an elongated smoking article component; a length of air permeable material wrapped about a section of said component; a band of air impermeable, heat shrinkable material disposed at least in part between said component section and said air permeable material in position so as normally to close the air permeable material against the passage of air while at the same time leaving a longitudinal passage for smoke through said component; and a body 7 8 disposed in and at least partially blocking said longituthe air permeable material to admit outside air into the dinal passage whereby when said heat shrinkable matearticle, wherein said body is formed of a compressible rial is heated it will shrink onto said body thereby at filter material.

least partially restricting said passage and uncovering 

1. A smoking article comprising: an elongated smoking article component; a length of air permeable material wrapped about a section of said component; a band of air impermeable, heat shrinkable material disposed at least in part between said component section and said air permeable material in position so as normally to close the air permeable material against the passage of air while at the same time leaving a longitudinal passage for smoke through said component; and a body disposed in and at least partially blocking said longitudinal passage whereby when said heat shrinkable material is heated it will shrink onto said body thereby at least partially restricting said passage and uncovering the air permeable material to admit outside air into the article, wherein said body is formed of a material impermeable to air and smoke.
 2. A smoking article comprising: an elongated smoking article component; a length of air permeable material wrapped about a section of said component; a band of air impermeable, heat shrinkable material disposed at least in part between said component section and said air permeable material in position so as normally to close the air permeable material against the passage of air while at the same time leaving a longitudinal passage for smoke through said component; and a body disposed in and at least partially blocking said longitudinal passage whereby when said heat shrinkable material is heated it will shrink onto said body thereby at least partially restricting said passage and uncovering the air permeable material to admit outside air into the article, wherein said body is formed of a compressible filter material. 